1. Field of the Invention
The invention relates in general to apparatus and method for melting furnaces, and, in particular, to method and apparatus for melting furnaces which are particularly adapted to the efficient melting of finely divided materials in the presence of oxygen without excessive oxidation.
2. Description of the Prior Art
Previous furnaces for melting finely divided materials in air, such as, for example, thin walled aluminum cans, often permitted excessive oxidation of the feedstock. This significantly reduced the efficiency of the operation. Previous expedients generally introduced the feedstock onto the surface of a molten mass and allowed the finely divided feed stock to melt down into the mass. Thin walled aluminum can feedstock, for example, oxidizes rapidly, and sometimes even ignites, as soon as it reaches its melting point. Because of the physical form of thin walled cans they are particularly difficult to melt efficiently.
Many times, for example, thin walled can feedstock, as delivered to a melting furnace, contains hydrocarbon materials in the form of paint or lacquer on the can, or residues of product within the can. Previously, disposing of these hydrocarbons safely, efficiently and without polluting was difficult.
Melting furnaces are generally operated to turn finely divided metallic feedstock into ingots. Previously it had been generally impossible to operate such melting furnaces efficiently in ambient air without releasing significant pollutants.
These and other difficulties of the prior art have been overcome according to the present invention.